1. The purchases reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by Wilks Brothers, LLC on May 5, 2017.

2. These shares are owned directly by Wilks Brothers, LLC.

3. See Remarks.

4. These shares are owned directly by SDW Investments, LLC.

Remarks:

Wilks Brothers, LLC is a 10% owner of the Common Stock. Wilks Brothers, LLC may be deemed to be a member of a group with Dan H. Staci Wilks, Farris Wilks and SDW Investments, LLC for purposes of Section 13(d) of the Exchange Act. Dan H. Wilks is the managing member of Wilks Brothers, LLC and the managing member of SDW Investments, LLC. Staci Wilks is the managing member of SDW Investments, LLC. Farris Wilks is the managing member of Wilks Brothers, LLC. Dan H. Wilks and Staci Wilks are husband and wife and Dan H. Wilks and Farris Wilks are brothers. SDW Investments, LLC beneficially owns 6,490,300 shares of Common Stock. Each Reporting Person disclaims beneficial ownership of all equity securities reported herein except to the extent of its respective pecuniary interest therein, and the filing of this Form 4 shall not be construed as an admission that any such Reporting Person is the beneficial owner of any equity securities covered by this Form.